深部高应力岩体新型吸能锚杆锚固机制及围岩耦合力学机理研究

The characteristics of high stress in deep rock mass will induce rock burst or large deformation failure. Accordingly, the rock bolt will be failed by pull, shear or bending, which influences the safety of rock engineering. This project, which is established by the condition of joint gap, will be evaluated by laboratory tests, numerical simulation and analytical methods. Thus, the anchorage performance and mechanism of new types of energy-absorbing rock bolts under pull-and-shear loading is analysed. The coupling mechanism of bolt type, displacing/loading angle, rock strength and joint gap opening will be conducted with a new developed bolt test rig. The scope of laboratory tests focuses on the quantitative contribution of energy-absorbing rock bolts to bolted rock joint. Based on the laboratory test results, a new "3-Spring" module will be built in order to simulate the bolt resistance from tension and shear accurately. Furthermore, a 3D numerical model will be setup to study the plastic zone distribution, the distributions of shear stress and axial stress and the strain component in large deformation. By developing the constitutive equations of rock bolts and the energy-absorbing bolt-rock mass system, the energy dissipation and the shear strength criterion of bolted joint will be further researched. In conclusion, the research result of this project will provide new theory and important reference for safety mining as well as rock support in deep rock mass.

深部岩体中高地应力的特征极易诱发岩爆或大变形等灾害问题，导致锚杆出现拉断、剪坏和扭曲等失效现象，严重影响岩体工程的安全性。本项目针对深部锚固节理岩体张裂的情况，运用室内试验、数值模拟和理论分析相结合的方法，研究岩体拉—剪组合荷载下新型吸能锚杆的锚固机制和力学机理。利用自行研制的新型锚杆测试系统，分别研究锚杆类型、位移加载角、岩体强度和初始裂隙张开度等因素的耦合力学机理，探明吸能锚杆对锚固岩体的单独定量贡献。开发能准确模拟锚杆抵抗拉力和剪力的“3-Spring”数值单元并进行三维建模，重点研究围岩塑性区、解耦后锚固段的剪应力、轴力及大变形应变量的非线性分布规律。通过建立锚杆能量本构方程和吸能锚杆—围岩耦合系统能量方程，研究能量的演化规律，最终建立吸能锚杆锚固结构面抗剪强度计算准则。研究成果可为深部岩体工程的安全开挖和加固支护提供理论支撑，并为相关工程设计提供重要参考。

基于新型组合荷载试验系统，研究吸能锚杆在深部岩体中拉—剪组合荷载作用下的锚固机理和作用模式。研究了不同类型锚杆、位移加载角、岩体和裂隙张开度等因素影响下的锚固大变形锚固机理。建立符合常规锚杆与新型吸能锚杆的三线性拉—剪数值仿真模型单元，研究了总荷载、总位移、变形剪应力、轴力的分布规律及变形中杆体应力及荷载分布。创新性提出全注浆的岩石锚杆在拉剪复合加载作用下的解析模型。构建锚杆—锚固介质—围岩受力状态的三维力学模型，可有效预测节理岩体滑动过程中注浆锚杆的总载荷和总位移，并定义了位移角和加载角的解析关系。基于裂隙岩体能量转化机制，研究含水平交叉裂隙、垂直交叉裂隙岩石试样的力学特性，分析不同应力条件下试样的能量吸收和损耗机制，研究总能量、弹性应变能和耗散能之间的关系。基于锚杆与围岩松动圈理论并结合工程现场情况，提出新型组合支护结构，通过巷道收敛性、边界位移、底鼓等因素验证了本研究内容成果的可为工程开挖支护提供理论支持。